full issue - Association of Biotechnology and Pharmacy

Current Trends in Biotechnology and PharmacyVol. 5 (1) 1054-1059 January 2011. ISSN 0973-8916 (Print), 2230-7303 (Online)Investigations on Microbial Resistance among Bacteria Dwellingin Indian SoilsC. Ganesh Kumar*, Joveeta Joseph and Ahmed KamalChemical Biology Laboratory,Indian Institute of Chemical TechnologyUppal Road, Hyderabad 500 607, India*For correspondence - cgkumar@iict.res.in1054AbstractThere is growing evidence that bacteria thatliving in diverse soil environments are gainingmulti-drug resistance. Recent functional screensand the growing information of metagenomicdatabases are also revealing the presence of anunexpected density of resistance genes in theenvironment, the antibiotic resistome. To explorethis reservoir, we isolated 15000 morphologicallydiverse microorganisms directly from soilsamples, and constructed a diverse library of 264resistant isolates. Without exception, all the 264isolates were found to be resistant to at least oneantibiotic. Multi-drug resistance was observed formore than 3 antibiotics in 83% of the isolates,while five strains showed resistance to more than10 antibiotics of the 15 antibiotics tested in thelibrary. These results indicate that soil bacteriaare a reservoir of antibiotic resistance with greatergenetic diversity than previously accounted for.Keywords: antibiotic; resistance; soil isolates;bacteria; IndiaIntroductionBacterial infections continue to be oneof the leading causes of morbidity and mortalityworldwide, despite the availability of diversearsenal of chemotherapies, attributed in part tothe evolution and dissemination of antibioticresistance genes (1). Traditional approaches toantibiotic resistance have involved extensiveresearch on human pathogens, limiting efforts toonly clinically identified mechanisms. It is nowbecoming increasingly evident, however, thatenvironmental forces have greatly impacted thedeterminants that have emerged clinically. Amongthe first to be recognized publicly was the impactof the agricultural use of antibiotics as animalgrowth promoters (1). Since 1940s, the extensiveuse of antimicrobials (2) and disposal of healthcareproducts, etc. contain resistance determinantsthat induce resistance in microorganismstowards various antibiotics (3). This use ofantibiotics in agriculture has resulted in the spreadof strains such as vancomycin-resistantenterococci in both farm animals exposed toantimicrobials and humans in contact with theanimals (4), and has been directly linked to thedevelopment of drug-resistant infections (1).Considering the growing body of evidencesuggesting that clinical resistance is intimatelyassociated with mechanisms foundenvironmentally, there is a clear need to expandthe focus to include non-pathogenic organisms inantibiotic research. In doing so, it may be possibleto establish strategies to predict resistance beforeit emerges clinically as well as develop diagnostictechniques and therapeutic strategies toInvestigations on Microbial Resistance among Bacteria Dwelling in Indian Soils